Effect Of Metal Electrodes Research Articles

The effect of metal electrodes and deposition angle on linearity of sculptured TiO2 humidity microsensors

The effect of metal electrodes and deposition angle on linearity of sculptured TiO2 humidity microsensors

Influence of metal electrodes on the irradiation resistance of HZO ferroelectric thin film capacitors and mechanism analysis

In application scenarios such as astronautics, high-altitude aircraft, medical radiography, high-energy physics, and nuclear power plants, the irradiation resistance of electronic components is one of the basic requirements for their reliability. HfO2-based ferroelectric films have the advantages of high CMOS process compatibility, good miniaturizability, low operating voltage, and excellent irradiation resistance, which are the core materials for the new generation of irradiation resistance ferroelectric memories. In this paper, two kinds of metal-electrode ferroelectric capacitors, W/Hf0.5Zr0.5O2/W (WW) and Pt/Hf0.5Zr0.5O2/Pt (PP), have been prepared, and three gradient γ-irradiation experiments have been carried out on the two kinds of ferroelectric capacitors. The effect of metal electrodes on the irradiation resistance of Hf0.5Zr0.5O2 ferroelectric thin films was carefully investigated by comparing and analyzing the statistical laws of polarization change and rectangularity change before and after irradiation of a large number of devices. The experimental results show that the WW devices have better irradiation resistance than PP devices, and we further explain the irradiation resistance mechanism by first-principle calculations and finite element analysis to verify the credibility of the experimental results. Finally, we conducted a comparative test of the fatigue and wake-up characteristics of the WW devices before and after irradiation, and the results show that the prepared W/Hf0.5Zr0.5O2/W devices can withstand very high total γ-dose radiation, reaching up to 13.86 Mrad(Si), and they are very suitable for the application of irradiation resistant electronics.

Enhancing the performance of TiO2 nanotube-based hydrogen sensors through crystal structure and metal electrode

In this research, the effect of metal electrodes and crystalline phase on gas detection of titanium dioxide (TiO2) nanotube-based hydrogen (H2) sensors was investigated. TiO2 nanotubes were produced using glycerol-based electrolyte and annealed at 300 °C and 700 °C to change the anatase and rutile crystalline phases, respectively. TiO2 nanotubes were coated by platinum (Pt), palladium (Pd), gold (Au) and silver (Ag) electrodes to fabricate metal/TiO2 nanotubes Ti H2 sensor devices and then the current-voltage (I–V) characteristics were investigated at room temperature. The structural properties of TiO2 nanotubes were characterized by SEM, FE-SEM, XRD, and Raman techniques. The H2 detection properties of the sensors were examined at the 1000 ppm - 5% H2 concentration range. The crystal structure and metal electrodes are the main factors that affect the H2 sensing properties of TiO2 nanotube-based sensors. The effect of crystal forms on sensitivity was not the same as for metal electrodes. The underlying sensing mechanisms for different types of metal electrodes and crystal structures are discussed and the relevance of their sensing performance to nanotubes and electronic properties is investigated. In addition, discussion of each metal electrode and crystal structure will make important contributions to the development of H2 sensors. The Pd-coated device annealed at 700 °C showed the best detection performance.

The Electrical Conductivity of Methylene-Methyliminomethyl Formamidine Molecular Nanowire via DFT and QTAIM Theory

The effect of metal electrodes on methylene-methyliminomethyl formamidine (MMF) molecule has been calculated by Density functional analysis using Gaussian09 program package. The various applied electric fields (0.00 – 0.26 VÅ-1) altered the geometrical parameters and the corresponding electrostatic and transport properties of the molecule has been analyzed. The variations in the atomic charges (MPA, NPA) of the molecule for the various applied electric fields have been compared. The HOMO-LUMO gap of the molecule for zero bias is 1.904 eV, as the field increases this gap decreases to 0.272 eV. The ESP shows the potential difference between charges accumulated of the molecule for various applied electric fields. The applied electric field polarizes the molecule, in consequence of that the dipole moment of the molecule decreases from 9.65 to 8.82 Debye. The small decrease of dipole moment shows that the molecule exhibits smaller conductivity.

Effects of metallic electrodes on the thermoelectric properties of zigzag graphene nanoribbons with periodic vacancies

We theoretically analyze the thermoelectric properties of graphene quantum dot arrays (GQDAs) with line- or surface-contacted metal electrodes. Such GQDAs are realized as zigzag graphene nanoribbons (ZGNRs) with periodic vacancies. Gaps and minibands are formed in these GQDAs, which can have metallic and semiconducting phases. The electronic states of the first conduction (valence) miniband with nonlinear dispersion may have long coherent lengths along the zigzag edge direction. With line-contacted metal electrodes, the GQDAs have the characteristics of serially coupled quantum dots (SCQDs) if the armchair edge atoms of the ZGNRs are coupled to the electrodes. By contrast, the GQDAs have the characteristics of parallel quantum dots if the zigzag edge atoms are coupled to the electrodes. The maximum thermoelectric power factors of SCQDs with line-contacted electrodes of Cu, Au, Pt, Pd, or Ti at room temperature were similar or greater than 0.186 nW K−1; their figures of merit were greater than three. GQDAs with line-contacted metal electrodes have much better thermoelectric performance than surface contacted metal electrodes.

Synthesis of a large area ReS2 thin film by CVD for in-depth investigation of resistive switching: effects of metal electrodes, channel width and noise behaviour.

The anisotropic crystal structure and layer independent electrical and optical properties of ReS2 make it unique among other two-dimensional materials (2DMs), emphasizing a special need for its synthesis. This work discusses the synthesis and in-depth characterization of a 1 × 1 cm2 large and few layered ReS2 film. Vibrational modes and excitonic peaks observed from the Raman and photoluminescence (PL) spectra corroborated the formation of a ReS2 film with a 1.26 eV bandgap. High resolution transmission electron microscopy (HRTEM) images and selected area electron diffraction (SAED) patterns inferred the polycrystalline nature of the film, while cross-sectional field emission scanning electron microscopy (FESEM) indicated planar growth with ∼10 nm thickness. The chemical composition of the film analysed through X-ray photoelectron spectroscopy (XPS) indicated the formation of a ReS2 film with a Re : S atomic ratio of 1 : 1.75, indicating a small amount of non-stoichiometric RexSy. Following the basic characterization studies, the ReS2 film was tested for resistive switching (RS) device application in which the effects of different metal electrodes (Pt/Au and Ag/Au) and different channel widths (200, 100, and 50 μm) were studied. The highest memory window equal to 108 was obtained for the Ag/Au electrode while Pt/Au showed a memory window of 102. RS for the former was ascribed to the formation of a conducting filament (CF) because of the migration of Ag+ ions, while defect mediated charge carrier transport led to switching in the Pt/Au electrode. Furthermore, the RHRS/RLRS ratio achieved in this work (108) is also of the highest magnitude reported thus far. Furthermore, a comparison of devices with Ag/Au electrodes but with different channel widths (50, 100 and 200 μm) gave insightful results on the existence of multiple resistance states, device endurance and retention. An inverse relationship between the retention time and the device's channel width was observed, where the device with a 50 μm channel width showed a retention time of 48 hours, and the one with a 200 μm width showed stability only up to 3000 s. Furthermore, low frequency noise measurements were performed to understand the effect of defects in the low resistance state (LRS) and the high resistance state (HRS). The HRS exhibited Lorentzian noise behaviour while the LRS exhibited Lorentzian only at low current bias which converged to 1/f noise at higher current bias.

Effect of metal electrodes on the steady-state leakage current in PZT thin film capacitors

Effect of metal electrodes on the steady-state leakage current in PZT thin film capacitors

Effect of Metal Electrodes on Aging-Induced Performance Recovery in Perovskite Solar Cells.

For commercialization of perovskite solar cells (PSCs), it is important to substitute the alternative electrode for Au to decrease the unit cost. From the early stage, Ag exhibits a potential to be a good counter electrode in PSCs; however, there is an abnormal s-shaped J-V curve with the Ag electrode, and it is recovered as time passes. The perception of the aging-induced recovery process and refutation of the raised stability issues are required for commercial application of Ag electrodes. Herein, we compared the aging effect of PSCs with Ag and Au electrodes and found that only devices with Ag electrodes have a dramatical aging-induced recovery process. We observed the change of photoelectronic properties only in the devices with Ag electrodes as time passes, which mainly contributes to recovery of the s-shaped J-V curve. We verified the work function change of an aged Ag electrode and its mechanism by photoelectron spectroscopy analysis. By comparing the light stability under 1 sun intensity illumination, we can assure the practical stability of Ag electrodes in case of being encapsulated. This work suggests the profound understanding of the aging-induced recovery process of PSCs and the possibility of commercial application of Ag electrodes.

Effect of Metallic Electrodes Ensemble on Charge Transport Characteristics of Cytosine Based Molecular Devices

The charge transport through molecular devices using an ensemble of metal electrodes having nucleobase cytosine as the central molecule has been envisaged using a combination of semi-empirical Extended Huckel Theory and Non Equilibrium Green Function (NEGF). FFT-2D computational approach has been effectively applied to elucidate the electron transport characteristics of these molecular devices under both equilibrium as well as non-equilibrium states. The charge transport parameters viz. Device Density of States, Transmission Spectrum, I–V curve, G–V curve and HOMO-LUMO Gap are measured to exhibit the charge transport properties. By comparing the obtained quantum transport properties, we observe that silver remains the best choice among the three electrode materials under study as the molecular device with the silver electrodes exhibits the lower HOMO-LUMO Gap with increased current and conductance for the higher bias voltages in contrast to the other two configurations which show comparatively higher value of HOMO-LUMO Gap. Hence, the molecular device with the silver electrodes has greater possibility of getting utilized as a switch in DNA based nano-electronics applications.

27.3: Invited Paper: Electrochemical study on wet etching of copper/molybdenum alloys in thin film transistors

As copper metallization process is widely adopted by Flat panel display industry, cost for waste treatment such as fluorine ions in copper wet etchant also dramatically increased. Reduction of fluorine ion in copper metallization process, will be a key environment friendly business issue in near future. In this paper, we developed new MoK copper barrrier layer for IGZO and LTPS application which can be easily wet‐patterned in copper wet etchant without etch residue. The effects of metal electrode on the electrical performance of back channel etching type amorphous In‒Ga‒Zn‒O thin film transistor have been studied. From secondary ion mass spectroscopy depth analysis, the detected molybdenum content on IGZO surface after wet patterning was greatly reduced by 10 times compared with pure molybdenum. In addition, MoK showed a better thermal resistance properties compared with pure molybdenum. After the MoK/copper/MoK tri‐layers were annealed at 400°C for 1 hour, the electrical resistance was decreased from 5.7 uohm‐cm to 3.2 uohm‐cm while pure molybdenum tri‐layer showed dramatic increase after thermal annealing. The reduced molybdenum residue after wet patterning also influenced the electrical properties of back channel etching type IGZO TFTs. The measured mobility lied between 10∼14 cm2/V.sec and contact resistance was about 0.5 Mohm which is comparable with reported values. The enhanced device performance and thermal stability were interpreted in terms of electron density change and intermetallic compound formation at Cu/MoK interface.

Theoretical insights and experimental characterization of $$\hbox {HfO}_2$$ HfO 2 -based OxRRAMs operation

The intensive research in resistive random access memories (RRAM) field has brought in significant improvements in the performance, optimization and reliability of the devices as well as more understanding on their operation. This was made possible through the combination of different tools starting from material engineering to device characterization, modeling and simulations. In this review, we bring an overview of our recent work on RRAM through experimental characterization and first-principles calculations. We explore the effects of metal electrodes on the switching performance and conductive filament (CF) stability of $$\hbox {HfO}_2$$ oxide-based RRAM (OxRRAM). With the insight gained from the experimental data, we employ first-principles calculations to have a better microscopic understanding on OxRRAM operation. We show that CF stability and device operating voltages strongly depend on the electrode material. Ti being an electrode material of high interest, we investigate the type of $$\hbox {Ti/HfO}_2$$ interface that may be formed and propose a probable composition. We also study the formation and migration of extended Frenkel-pair (EFP) defect in $$\hbox {HfO}_2$$ which we consider to be the prototype defect responsible for OxRRAM degradation leading to CF formation. This EFP emission occurs through a cascading migration of O atoms inside $$\hbox {HfO}_2$$ lattice. Based on EFP formation and diffusion, we present a simplified CF formation model. Finally, we study low resistance data retention failure in OxRRAM through $$\hbox {HfO}_2$$ , $$\hbox {Hf}_{1x}\hbox {Al}_{2x}\hbox {O}_{2+x}$$ (HfAlO) and $$\hbox {Hf}_{1-x}\hbox {Ti}_{x}\hbox {O}_{2}$$ (HfTiO) type of cells. We link its origin to the lateral diffusion of oxygen vacancies at the constriction/tip of the conductive filament in $$\hbox {HfO}_2$$ -based RRAM.

P-56: Eco-Friendly Copper Metallization for IGZO and LTPS with New Molybdenum Barrier Layer

As copper metallization processes have been widely adopted in the panel display industry, waste treatment costs including those for fluorine ions in copper wet etchant have also dramatically increased. The reduction of fluorine ions in copper metallization processes will be a key eco-friendly business issue in the near future. For this paper, new molybdenum alloy as a copper barrrier layer for IGZO and LTPS applications was developed that can be easily wet-patterned in copper wet etchant without etch residue. First, the effects of metal electrodes on the electrical performance of back channel etching type amorphous In-Ga-Zn-O thin film transistors were studied. Then, a secondary ion mass spectroscopy depth analysis revealed that the detected molybdenum content on the IGZO surface after wet patterning experienced a ten-fold reduction compared to pure molybdenum. In addition, new molybdenum alloy showed better thermal resistance properties compared to pure molybdenum. After the Mo alloy/copper/Mo alloy tri-layers were annealed at 400 °C for 1 hour, the electrical resistance decreased from 5.7 µohm-cm to 3.2 µohm-cm, while the pure molybdenum tri-layer showed a dramatic increase after thermal annealing. The reduced molybdenum residue after wet patterning also influenced the electrical properties of the back channel etching type IGZO TFTs. The mobility measured between 10~14 cm2/V.sec and the contact resistance was about 0.5 Mohm. Both value were comparable to reported value.

Effect of Metal Electrodes on Surface Acoustic Wave Properties in Bulk Z-Cut GaN Crystal

The effect of metal electrodes on surface acoustic wave (SAW) properties in bulk semi-insulating Z-cut GaN crystal was measured for the first time. A SAW synchronous two-port resonator was used for these measurements. Such SAW parameters as velocity, electromechanical coupling coefficient, and reflection coefficient of a single reflecting strip were determined by matching the measured and calculated amplitude responses of the resonator for aluminum and gold electrodes at a frequency of about 240 MHz. It was found that for gold electrodes, the reflection coefficient of a single reflecting strip is much larger compared with that of aluminum. Changes of resonance frequency against temperature were measured in the temperature range from -20 °C to 80 °C and linear temperature coefficient of frequency of about -23 ppm/°C was obtained. Isotropic SAW properties in the propagation plane, low temperature coefficient of frequency, and possibility of integration with active devices make the bulk Z-cut GaN crystal attractive for practical applications.

Effect of metal electrode on characteristics of gamma-irradiated silicon carbide detector

Silicon carbide (SiC) is a highly promising semiconductor neutron-detector material for harsh environments such as nuclear reactor cores and spent-fuel storage pools. In the present study, three 4H–SiC p–i–n diode detectors were fabricated as variations of those metal-electrode structures. The I–V characteristics and alpha-particle responses of the detectors were measured before and after gamma-ray exposure. The detector with a Ti/Au electrode showed the lowest change of leakage current after irradiation; none of the detectors showed any change in the charge-collection efficiency when a sufficient electric field was applied after gamma irradiation of up to 8.1 MGy.

Effects of metal electrodes and dielectric thickness on non-volatile memory with embedded gold nanoparticles in polymethylsilsesquioxane

Graphical abstractDisplay Omitted Highlights A memory device with gold nanoparticles in polymethylsilsesquioxane demonstrated. Effects of metal electrode types on the memory explained. Effects of p...

Effects of metal electrodes and dielectric thickness on non-volatile memory with embedded gold nanoparticles in polymethylsilsesquioxane

We fabricated non-volatile memories from metal-insulator-semiconductor structure to investigate the effects of different metal electrodes and dielectric thickness towards the electrical behaviour of the device. The insulator layer is a nanocomposite layer consists of embedded gold nanoparticles in polymethylsilsesquioxane. The AuNPs have an average size of 20nm. Gold and aluminium electrodes and different PMSSQ's thickness were used to examine their effects on the non-volatile memories (NVMs). NVMs with gold electrodes are reprogrammable and have a similar behaviour to a flash memory that can be erased and reprogrammed multiple times. However, NVMs made with aluminium electrodes are write-once-read-many. The transport mechanisms of the device have been described based on the I-V results.

Erratum: “Effects of Metal Electrode on the Electrical Performance of Amorphous In–Ga–Zn–O Thin Film Transistor”

Erratum: “Effects of Metal Electrode on the Electrical Performance of Amorphous In–Ga–Zn–O Thin Film Transistor”

Erratum: “Effects of Metal Electrode on the Electrical Performance of Amorphous In–Ga–Zn–O Thin Film Transistor”

Erratum: “Effects of Metal Electrode on the Electrical Performance of Amorphous In–Ga–Zn–O Thin Film Transistor”

Effects of Metal Electrode on the Electrical Performance of Amorphous In–Ga–Zn–O Thin Film Transistor

Effects of Metal Electrode on the Electrical Performance of Amorphous In–Ga–Zn–O Thin Film Transistor

Effects of Metal Electrode on the Electrical Performance of Amorphous In–Ga–Zn–O Thin Film Transistor

Effects of metal electrode on the electrical performance of amorphous In–Ga–Zn–O (a-IGZO) thin film transistor (TFT) have been studied. Electrical performances and interface stability between Mo, Al, and Cu electrode and a-IGZO semiconductor have been investigated before and after air-annealing. No inter-diffusion and interfacial reaction has been observed between Mo and a-IGZO and the turn-on voltage of the Mo electrode TFT was 0 V after annealing. As for Al, Al oxide was formed at the interface, and the number of conduction electrons in a-IGZO increased. Thus, a negative turn-on voltage was observed after air-annealing. As for Cu, Cu diffused into a-IGZO during air-annealing and acted as an acceptor. Therefore the a-IGZO TFT with a Cu electrode had a positive turn-on voltage and sub-threshold slope increased after air-annealing. These results indicate that the transistor performance can be affected by the metal types due to inter-diffusion or interfacial reaction between metal and a-IGZO.